Abstract: In this paper, a set of gait monitoring device for firefighters based on nine axis sensors (3- axis acceleration, 3- axis gyroscope and 3-axis magnetometer) is designed. The structure, device selection and system design of the device are studied. The device is insole type, which can be directly put in training shoes or fire boots. It can collect the movement posture of firefighters in real time. It has the function of virtual and real step monitoring, step phase analysis, support analysis, posture tracking, swing analysis, micro motion analysis, etc. The device can be used to detect the virtual and real steps in the training of firefighters. The measured gait data of firefighters can assist in evaluating the training intensity. The test results can provide scientific data support for the customized personalized foot protection equipment of firefighters, which is helpful to improve the coordination of firefighters and relieve the impact force of firefighters' knees.

Key words: firefighter; gait analysis, gait monitoring device, nine axis sensor